Avoiding ONU laser by optical modulation and remodulation

Abstract

Tuned lasers in the ONU's are eliminated in WDM PON by use of a burst mode transmission. An apparatus for communicating over a passive optical network comprises a transmitting portion operable to generate an optical signal comprising a first portion modulated with a first data signal and a second portion that is unmodulated and to transmit the optical signal over the passive optical network and a receiving portion operable to receive an optical signal comprising the second portion of the transmitted optical signal modulated with a second data signal.

1 . A method of communicating over a passive optical network comprising: 
 generating an optical signal modulated with a first data signal at a first network element;    transmitting the modulated optical signal over the passive optical network from the first network element to a second network element;    remodulating the received modulated optical signal with a second data signal at the second network element; and    transmitting the remodulated optical signal from the second network element to the first network element.    
   
   
       2 . An apparatus for communicating over a passive optical network comprising: 
 a transmitting portion operable to generate an optical signal modulated with a first data signal and to transmit the modulated optical signal over the passive optical network; and    a receiving portion operable to receive an optical signal comprising the transmitted optical signal remodulated with a second data signal.    
   
   
       3 . The apparatus of  claim 2 , wherein the transmitting portion comprises: 
 an optical modulator operable to modulate an unmodulated optical signal with the first data signal.    
   
   
       4 . The apparatus of  claim 2 , wherein the first data signal comprises a line code signal having a symbol rate greater than a symbol rate of the first data.  
   
   
       5 . The apparatus of  claim 2 , wherein the receiving portion comprises: 
 an optical demodulator operable to demodulate the received optical signal to recover the second data signal.    
   
   
       6 . An apparatus for communicating over a passive optical network comprising: 
 a receiving portion operable to receive an optical signal modulated with a first data signal over the passive optical network;    a remodulating portion operable to remodulate the received optical signal with a second data signal; and    a transmitting portion operable to transmit the remodulated optical signal over the passive optical network.    
   
   
       7 . The apparatus of  claim 6 , wherein the receiving portion comprises: 
 a power splitter operable to split the received optical signal between the receiving portion and the remodulating portion; and    a line code demodulator operable to detect the first data signal from the received optical signal.    
   
   
       8 . The apparatus of  claim 7 , wherein the optical signal modulated with the first data signal comprises a training interval and the line code demodulator further comprises a framing device operable to identify the training interval.  
   
   
       9 . The apparatus of  claim 8 , wherein the receiving portion further comprises: 
 circuitry operable to output a signal phase locked to the training interval signal that is locked to the downstream frame and clock identified by the framing device.    
   
   
       10 . The apparatus of  claim 9 , wherein the remodulating portion comprises: 
 a line code modulator operable to remodulate the received optical signal with a second data signal based on the signal phase locked to the training interval signal.    
   
   
       11 . The apparatus of  claim 6 , wherein the remodulating portion comprises: 
 a line code modulator operable to remodulate the received optical signal with a second data signal    
   
   
       12 . The apparatus of  claim 6 , wherein the transmitting portion comprises: 
 an optical amplifier operable to amplify the remodulated optical signal.    
   
   
       13 . An apparatus for communicating over a passive optical network comprising: 
 a beamsplitter operable to split a received optical signal between a receiving portion and a remodulating portion;    a remodulating portion operable to remodulate the received optical signal with a second data signal; and    a photodetector operable to detect the first data signal from the received optical signal.    
   
   
       14 . The apparatus of  claim 13 , wherein the remodulating portion comprises a silicon optical amplifier reflective operable to receive the modulated optical signal from the beamsplitter, to remodulate the received optical signal with the second data signal, and to reflect the remodulated optical signal back to the beamsplitter.  
   
   
       15 . A method of communicating over a passive optical network comprising: 
 generating at a first network element an optical signal comprising a first portion modulated with a first data signal and a second portion that is unmodulated;    transmitting the optical signal over the passive optical network from the first network element to a second network element;    modulating the second portion of the received optical signal with a second data signal at the second network element; and    transmitting the modulated second portion of the received modulated optical signal from the second network element to the first network element.    
   
   
       16 . An apparatus for communicating over a passive optical network comprising: 
 a transmitting portion operable to generate an optical signal comprising a first portion modulated with a first data signal and a second portion that is unmodulated and to transmit the optical signal over the passive optical network; and    a receiving portion operable to receive an optical signal comprising the second portion of the transmitted optical signal modulated with a second data signal.    
   
   
       17 . The apparatus of  claim 16 , wherein the transmitting portion comprises: 
 an optical modulator operable to modulate the first portion of an unmodulated optical signal with the first data signal and to not modulate the second portion of the unmodulated optical signal.    
   
   
       18 . The apparatus of  claim 17 , wherein the receiving portion comprises: 
 an optical demodulator operable to demodulate the received optical signal to recover the second data signal.    
   
   
       19 . An apparatus for communicating over a passive optical network comprising: 
 a receiving portion operable to receive an optical signal comprising a first portion modulated with a first data signal and a second portion that is unmodulated over the passive optical network;    a modulating portion operable to modulate the second portion of the received optical signal with a second data signal to form a second optical signal; and    a transmitting portion operable to transmit the second optical signal over the passive optical network.    
   
   
       20 . The apparatus of  claim 19 , wherein the receiving portion comprises: 
 a power splitter operable to split the received optical signal between the receiving portion and the unmodulating portion; and    a demodulator operable to detect the first data signal from the received optical signal.    
   
   
       21 . The apparatus of  claim 20 , wherein the demodulator further comprises a framing device operable to identify the second portion of the received optical signal.  
   
   
       22 . The apparatus of  claim 21 , wherein the modulating portion comprises: 
 a modulator operable to modulate the second portion of the received optical signal with a second data signal based on the identification of the second portion of the received optical signal from the framing device.    
   
   
       23 . The apparatus of  claim 22 , wherein the transmitting portion comprises: 
 an optical amplifier operable to amplify the second optical signal.    
   
   
       24 . An apparatus for communicating over a passive optical network comprising: 
 a beamsplitter operable to split a received optical signal between a receiving portion and a modulating portion, the received optical signal comprising a first portion modulated with a first data signal and a second portion that is unmodulated;    a modulating portion operable to modulate the second portion of the received optical signal with a second data signal to form a second optical signal; and    a photodetector operable to detect the first data signal from the received optical signal.    
   
   
       25 . The apparatus of  claim 24 , wherein the modulating portion comprises a silicon optical amplifier reflective operable to receive the second portion of the optical signal from the beamsplitter, to modulate the second portion of the optical signal with the second data signal to form the second optical signal, and to reflect the second optical signal back to the beamsplitter.